Donnie Miller, AgCenter weed scientist, said Italian ryegrass, even if it’s not herbicide-resistant, has been a problem for row crops. “It’s going to suck moisture out of the seedbed,” Miller said.

Because it is a winter annual, the weed could cause problems for wheat, Miller said. “It competes directly with the crop.”

In addition, Italian ryegrass seed can be comingled at harvest with wheat grain, causing quality issues when a crop is sold, Miller said.

Stephenson said the plant emerges in September and October. Then its emergence slows in December, but it emerges again in January.

He said farmers who neglect to treat the weed in the fall will pay more in the form of additional herbicide treatments in the spring before planting.

Stephenson said the MSU guidelines indicate that two applications of paraquat at a high rate can control it now and stop seed production, but this would be considered a salvage treatment.

It typically is found on roadsides, in ditches and on the edges of fields, he said, and farmers working their land unknowingly spread the seed across a field.

But Miller said Italian ryegrass is not as prolific of a seed producer as Palmer amaranth, which also has developed herbicide resistance, so farmers can see the gradual spread of the weed across the field.

“It’s like watching a hurricane versus a tornado,” Miller said. “With Italian ryegrass, you can see it coming.”

In addition to Italian ryegrass and Palmer amaranth, weeds recently found to have developed glyphosate herbicide resistance include johnsongrass, rice flatsedge and barnyardgrass.